JP5444250B2 - Recording element for water-based ink - Google Patents

Abstract

The present invention is directed to an image-recording medium comprising a paper support and, coated on one side of the support, in order: a lower ink-receiving layer, an upper gloss layer and, coated on the opposite side of the support, an inner layer comprising at least 75% by weight of fine inorganic particles and a binder, and an outer layer substantially consisting of a polymeric material. Another aspect of the present invention relates to an inkjet printing process.

Description

  The present invention relates generally to the field of printing and in particular to a recording element for aqueous inks. More specifically, the present invention relates to a recording element in the form of cut paper that has improved transport in a printing press and reduced curl tendency.

  Water-based inks are often the most preferred type for desktop printing processes, which are becoming ubiquitous in home and office environments where advanced personal computers and inkjet printers are now available. Due to the hydrophilic nature of absorbing ink, the ink receiving medium is in dynamic equilibrium with the environment with respect to moisture. Hydrophilic materials tend to swell when they absorb moisture. Any difference in expansion within the multilayer material will result in curling. Normally, photographic quality media is intended to print on only one surface, and therefore the expensive coating necessary to provide excellent image quality is only provided on one surface of the recording material. Differences in the absorption of environmental humidity by asymmetrically coated media result in undesirable curls. If printed on one surface with aqueous ink, even symmetrically coated media can curl.

  For aesthetic and practical reasons, ink-jet photographic paper curl is undesirable. The coated paper may show a tendency to curl in response to environmental factors (most importantly relative humidity) or, for example, during printing or in response to wetting or drying during manufacture. Curling can be induced in the coating through an asymmetric process during the manufacturing process or by humidity changes prior to its use in the printing press. Curled paper can be unsuitable for precise picking and feeding by a printing press. Even non-curled paper can curl upon rewetting with applied ink and cause head strikes or failure to transport. Eventually, curled prints can collide in the output tray of the printing press. For these reasons, the curl phenomenon can be a complex phenomenon. Nevertheless, manufacturers are anxious to minimize the curl of the inkjet receiver under various conditions.

  It is known that a backside coating on the support surface opposite the image-receiving layer provides curl reduction by balancing the curl tendency on both sides of the recording paper. For example, Idei et al., In U.S. Pat.No. 5,302,437, discloses a backcoat layer comprising inorganic particles and a binder, and recommends minimizing coating mass differences between the front and backside coatings. ing. While curl may be reduced, the problem of reliable media picking and feeding by the transport mechanism of the printing press may remain.

  Pre-cut standard size recording materials held in a stack are universally accepted by desktop printers for convenience. The transport mechanism of the printing press includes means for picking a single sheet from a stack of paper feeds at the beginning of the printing process. For reliable picking of exactly one sheet, this sheet maintains non-slip contact with the transport mechanism of the printing press, which usually includes a series of compliant rollers, and the media It is necessary to slide easily from the stack of supplies. The failure of “picking” and picking a plurality of sheets at a time is a problem that arises from a recording material having surface characteristics that are unsuitable for operation by the sheet supply mechanism of the printer.

  The slippage of a single sheet from the stack is affected by the coefficient of static friction between the front surface and the back surface and the adhesive force with the transport roller on the back surface. Owatari et al. In US Pat. No. 5,928,787 discloses a backside coating of an aqueous binder and a higher fatty acid salt. The problem with this approach is that large amounts of expensive polymer are required to offset the tendency for large coat mass curl on the front of photographic quality media.

  Ishiyama et al., In US Pat. No. 6,436,514, comprises an ink-receiving layer and a glossy layer on the front side of a support, and a pigment and a binder on the surface of the support opposite to these coating layers. A porous image-recording element with a layer is disclosed, wherein the coefficient of static friction between the glossy layer and the backcoat layer is 0. 0 ° C. at 20 ° C. and 60% relative humidity (“RH”). 9 or less.

  When the amount of the binder in the back layer is small, the conveyance in the printing press may tend to be unreliable under conditions of low temperature and low humidity. In addition, the binding properties of the backside layer can be low, resulting in dust generation problems during the media slitting and cutting manufacturing operations and during media transport through the printing press. Another problem with the low binding property of the back surface is that the back surface is peeled off when an adhesive is applied to the back surface for the purpose of sticking to the mount. On the other hand, if the level of binder in the coating composition for the back side increases significantly, the viscosity of the coating composition increases and the composition must be diluted, increasing the need for drying, Or it results in a decrease in manufacturing productivity.

  The object of the present invention is to reduce the tendency of curling under various conditions, to improve the picking and feeding reliability of cut media sheets in the printing press, and to have high back coating binding properties, gloss It is to provide a porous ink receiving medium.

  The present invention is directed to overcoming one or more of the problems set forth above. Briefly summarized, according to one aspect of the present invention, there is provided a support and at least one ink-receiving layer coated on one surface of the support, and on the opposite surface of the support. There is also provided an image recording medium comprising an inner layer containing at least 50% by mass of fine inorganic particles and a binder, and an outer layer substantially consisting of a polymer material.

  Another aspect of the present invention relates to an inkjet printing method including inkjet printing on the inkjet recording medium.

  The ink recording medium of the present invention provides a glossy, photographic quality image, ensures that it is relatively flat, and is reliably picked and transported from the stack by a printing mechanism. The binding properties of the back layer are sufficient to prevent dusting and delamination during manufacturing operations, printing and mounting. Importantly, the tendency of curl under various conditions is significantly reduced by using the present invention.

  The particle size mentioned here is the median particle size measured by light scattering measurement of diluted particles dispersed in water, unless otherwise noted, NANOTRAC (Microtac Inc.), MALVERN, or CILAS Measured using laser diffraction or photon correlation spectroscopy (PCS) using equipment or essentially equivalent methods, this information is often given in product documentation. For particle sizes greater than 0.3 micrometers, particle measurements are by Micromeritics SediGraph® 5100 or equivalent method. For particle sizes of 50 nm or less, particle measurement is by direct method, transmission electron microscopy (TEM) or equivalent method for each sample. Unless otherwise specified, the particle size refers to the secondary particle size.

  As used herein, the terms “upper”, “upper”, “upper”, “lower”, “lower”, “lower”, etc. refer to the layer (s) in the inkjet media on the support. However, it does not necessarily indicate that these layers are directly adjacent or have no intermediate layers.

  In a typical ink jet recording or printing system, ink droplets are emitted from a nozzle at high speed toward a recording element or medium to produce an image on the medium. The ink droplet or recording liquid usually contains a recording agent such as a dye or pigment and a large amount of solvent. This solvent or carrier liquid is usually made from an aqueous mixture and contains, for example, water and one or more organic materials such as monohydric alcohols, polyhydric alcohols, and the like.

  Ink jet recording elements typically comprise at least one ink-receiving layer, or “IRL”, comprising inorganic, polymer or organic-inorganic composite particles, a polymer binder, and optionally additives such as a dye fastness enhancer or mordant. ”On at least one surface of the support. These particles can vary in chemical composition, size, shape, and porosity within the particles. In this case, the printing liquid is absorbed into the open, interconnected pores of the IRL, and then a printed matter is obtained that immediately becomes dry to the touch by capillary action. Typically, the total volume of pores between interconnected particles of a porous medium (which may contain one or more layers) is the total volume of applied ink that forms the image. The volume is too large to hold.

  Basically, organic and / or inorganic particles in the porous layer form pores by spacing between the particles. A binder is used to hold these particles together. However, it is desirable that the amount of binder be limited in order to maintain a large pore volume. Too much binder will begin to fill the pores between the particles or beads, which will reduce ink absorption. On the other hand, too little binder can reduce the binding properties of the coating, which can lead to cracking.

  A glossy porous ink jet recording medium has one or more ink-receiving layers. Inkjet recording media designed exclusively for use with pigmented inks during inkjet printing can have only a single coat layer. However, ink jet recording media designed for use with either dye-based inks or pigment-based inks, or both, typically have at least two layers of coated ink receptive of different composition on a support. A base layer closer to the support and a glossy image-receiving layer, or "gloss layer", farther from the support.

  Those skilled in the art will appreciate that many factors can affect the curl tendency of inkjet recording media. For example, in the case of paper supports, these factors that contribute strongly to water absorption and stiffness should be noted, for example whether they are fiber sources, hard or soft materials, paper basis A method for making paper, including amount, fiber type and amount, sizing agent type and amount, and drying and calendering. The nature of the imaging surface coating and its method of manufacture, particularly the initial water content and drying method, interact with the support to determine the uncompensated curl tendency of the inkjet media.

  In manufacturing the ink jet recording element of the present invention, those skilled in the art will make adjustments within the scope of the present invention according to the inherent tendency of the media to curl.

As noted above, the present invention is directed to an inkjet recording element that includes a support having a front surface and a back surface, the inkjet recording element comprising:
(A) One or more porous ink receiving layers on the front surface of the support (the overall coverage of one or more ink receiving layers is 15 g / m ² or more, preferably 20 g / m ² or more, and in some embodiments (especially including alumina or alumina hydrate) 25 g / m ² or more), and (b) in order from this support on the back side of the support, Coated layer:
(I) A porous first back surface layer containing inorganic particles and a polymer binder of 4 to 50% by mass in solid content (the coverage of this first back layer is ² to 50 g / m ² ) And (ii) a non-porous material comprising 75% by weight or more, preferably 85% by weight or more, more preferably 95% by weight or more of a polymer material in solid content on the porous first back layer. The uppermost second back layer (the coverage of the second back layer is ² to 10 g / m ² ). Such a non-porous layer does not contain interconnected pores formed by the particles, and preferably is essentially free of particles that allow liquid capillary action. Most preferably, the particles are essentially absent from the surface of this layer, so that the coefficient of friction of the back surface of the ink jet recording element is essentially the non-porous top second back layer polymer content. Determined by quantity.

  For the back layer, the inorganic particles in the porous first back layer are preferably selected from the group consisting of clay (preferably kaolin), calcium carbonate, boehmite, or combinations thereof. In a preferred embodiment, the inorganic particles in the porous first back layer have at least one dimension less than 1 micrometer. Accordingly, flatter particles having a larger maximum dimension than spherical particles can be used. Unless otherwise specified, the dimensions are median dimensions as described above.

  In a particularly preferred embodiment, the ink jet recording element of the present invention has a porous first back layer, in which the inorganic particles are selected from kaolin, boehmite and / or calcium carbonate and from 100 nm to It has a median particle size of 2 micrometers. More preferably, the inorganic particles in the porous first back layer are 65% or more, more preferably 80% or more of the same kind of materials among the three kinds of kaolin, boehmite and / or calcium carbonate. .

  As the binder, any suitable polymer material can be used in the porous first back surface layer or in the non-porous second back surface layer. In preferred embodiments, the polymeric material is a hydrophilic polymer such as poly (vinyl alcohol), poly (vinyl pyrrolidone), gelatin, cellulose ether, poly (oxazoline), poly (vinyl acetamide), partially hydrolyzed poly (vinyl acetate / vinyl). Alcohol), poly (acrylic acid), poly (acrylamide), poly (alkylene oxide), sulfonated or phosphorylated polyester and polystyrene, casein, zein, albumin, chitin, chitosan, dextran, pectin, collagen derivatives, collodion, agar, These include Arrowroot, Guar, Carrageenan, Tragacanth, Xanthan, and Rhamsan. Preferably, the hydrophilic polymer is poly (vinyl alcohol), hydroxypropylcellulose, hydroxypropylmethylcellulose, poly (alkylene oxide), poly (vinyl pyrrolidone), poly (vinyl acetate) or copolymers thereof or gelatin. Usually, good results are also obtained with polyurethane, vinyl acetate-ethylene copolymer, ethylene-vinyl chloride copolymer, vinyl acetate-vinyl chloride-ethylene terpolymer, acrylic polymer, or derivatives thereof. can get. Preferably, the binder is a water-soluble hydrophilic polymer, most preferably polyvinyl alcohol or the like.

  Other polymer materials such as hydrophobic materials such as poly (styrene-co-butadiene), polyurethane latex, polyester latex, poly (n-butyl acrylate), poly (n-butyl methacrylate), poly (2-ethylhexyl acrylate) , A copolymer of n-butyl acrylate and ethyl acrylate, a copolymer of vinyl acetate and n-butyl acrylate, and the like can also be used. Poly (styrene-co-butadiene) latex is a preferred hydrophobic material. Mixtures of hydrophilic binders and latex binders, such as PVA (polyvinyl alcohol) poly (styrene-co-butadiene) latex, can also be used.

  In order to provide mechanical durability to the porous first back layer or the non-porous top second back layer, a small amount of a cross-linking agent acting on the polymer material discussed above may be added. Such additives improve the cohesive strength of this layer. Cross-linking agents such as carbodiimides, multifunctional aziridines, aldehydes, isocyanates, epoxides, polyvalent metal cations, vinyl sulfones, pyridiniums, pyridylium dication ethers, methoxyalkyl melamines, triazines, dioxane derivatives, chromium alum, zirconium sulfate, boro An acid, a borate, or the like can be used. Preferably, the cross-linking agent is an aldehyde, acetal or ketal, such as 2,3-dihydroxy-1,4-dioxane.

  In the non-porous uppermost second layer, the polymeric material can be a hydrophilic or hydrophobic polymeric material. Preferred hydrophilic polymers are polyester, polyurethane, polyvinyl pyrrolidone, or polyvinyl alcohol or modified polyvinyl alcohol. Most preferably, the polymeric material in the non-porous top second back layer is poly (vinyl alcohol). In the case of the hydrophobic polymer material in the non-porous uppermost second back layer, preferred examples include styrene-butadiene or poly (urethane).

  Preferably, the layer coated on the back side of the support is a near-infrared so that the printing press can reliably detect coded indicia that is printed on the back side of the support and absorbs infrared. Transparent enough.

  In one specific embodiment, the support may be a combination of the total coverage of the layers coated on the back surface, which may depend significantly on the support or material included in the front surface coating and the back surface coating. The ratio of the ink receiving layer on the front surface to the total coverage is 25 to 65%, preferably 30 to 60%.

  In one aspect of the present invention, the inorganic particles in the porous first back layer mainly include calcium carbonate particles. The term “precipitated calcium carbonate” is used herein to define calcium carbonate produced by a synthetic method and is not based on calcium carbonate found in nature. Preferably, in such an embodiment, the porous first back layer comprises precipitated calcium carbonate particles in an amount greater than 65% by weight, based on the total inorganic particles in this layer. The precipitated calcium carbonate can comprise a trigonal rhombohedral, orthorhombic, acicular or rhombohedral morphology, and combinations thereof.

  In particular, in one embodiment, the porous first back layer preferably comprises a binder in an amount of 5-15% by weight, more preferably 6-12% by weight, and 80% by weight or more of calcium carbonate particles. The calcium carbonate particles preferably have a median particle size of 0.4 to 5 micrometers and are less than 3 μm, more preferably less than 2 μm, most preferably 0.4 to 2 μm, such as 0.5 to It has a preferable size of 1.5 μm.

  Examples of decentered trihedral calcium carbonate that can be used include various ALBACAR PCC products available from Specialty Minerals Inc. (a subsidiary of Minerals Technologies Inc.). PCC materials with a decentered trihedron available from Specialty Minerals Inc. include ALBACAR HO, ALBACAR 5970 and VICALITY EXTRA LIGHT. Examples of other types of precipitated calcium carbonate include ALBAGLOS and ALBAFIL PCCs (rhombic), OPACARB PCC (needle-like) and VICALITY Heavy PCC (cubic), also available from Specialty Minerals Inc. Products). Other companies that make PCC include Pfizer and Solvay.

  In one preferred embodiment, the porous first back layer contains precipitated calcium carbonate mixed with other particles of 40% by mass or less based on the total mass of the inorganic particles. Is either organic and / or other inorganic particles and includes organic-inorganic composite particles, such as kaolin clay.

In another aspect of the present invention, the inorganic particles in the porous first back layer are mainly composed of alumina hydrate particles. As will be appreciated by those skilled in the art, the term “alumina hydrate” is used herein to represent the general formula:
Al ₂ O _3-n (OH) _2n · mH ₂ O
(N is an integer of 0 to 3, and m is a number of 0 to 10, preferably 0 to 5). In many cases, mH ₂ O represents the aqueous phase, which can be removed without participating in the formation of a crystal lattice. Therefore, m can take a value other than an integer. However, m and n are not 0 at the same time.

  Alumina hydrate crystals exhibiting a boehmite structure are usually layered materials, whose (020) plane forms a macro-plane and exhibits characteristic diffraction peaks. Besides perfect boehmite, it is called pseudo-boehmite and can take a structure containing excess water between (020) plane layers. The x-ray diffraction pattern of this pseudo-boehmite shows a broader diffraction peak than that of perfect boehmite. The term “boehmite” or “boehmite structure” is used herein to include both, unless otherwise specified, because perfect boehmite and pseudo-boehmite cannot be clearly distinguished from each other. For the purposes of this specification, the term “boehmite” means boehmite and / or pseudo-boehmite.

Boehmite and pseudo-boehmite are alumina hydrates, in particular aluminum oxyhydroxides, which are here defined by the general formula γ-AlO (OH) xH ₂ O (x is 0 to 1). . In the case of x = 0, this material is in particular balmite for pseudo-balmite, and in the case of x> 0 and when this material contains water in its crystal structure, this material Is known as pseudo-balm stone. Boehmite and pseudoboehmite are also described as Al ₂ O ₃ .zH ₂ O, when z = 0 this material is balmite and when 1 <z <2, This material is pseudo balm stone. The above materials are distinguished from aluminum hydroxide (eg, Al (OH) ₃ , bayerite and gibbite) and diaspore (α-AlO (OOH)) by their composition and crystal structure.

  In particular, in one embodiment, the porous first back layer preferably comprises a binder in an amount of 5-15% by weight, more preferably 6-12% by weight, and 80% by weight or more of aluminum hydrate particles. The aluminum hydrate particles preferably have a median particle size of 0.1 to 1.0 micrometers, less than 0.5 μm, more preferably less than 0.2 μm, and most preferably 0.1 to 0. It has a preferable size of 2 μm.

  In still another preferred embodiment of the present invention, the inorganic particles in the porous first back layer mainly include clay particles.

  In particular, in one embodiment, the porous first back layer preferably comprises 5-15% by weight, more preferably 6-12% by weight of binder, and 80% by weight or more of clay particles, The particles preferably have a median particle size of 0.5 to 5.0 micrometers and have a more preferred size of less than 3 μm, more preferably less than 2 μm, for example 0.5 to 1.0 μm.

  Examples of clay particles include kaolin clay, delaminated kaolin clay, and calcined clay. Preferred clays are kaolin clay, more preferably exfoliated. Examples of commercially available clays include HYDRAGLOSS 90 (Huber), POLYGLOSS 90 (Huber) and KAOFINE 90 (Thiele Kaolin). These clays may be dispersed alone in water, or a small amount (less than 1% by weight (w / w) of the clay) of an anionic dispersant (eg COLLOID 211, anionic polyacrylate) may be dispersed. May be added to facilitate the process.

  In embodiments where kaolin and other clay pigments are used in an amount of 50% by weight or more of the total inorganic particles, up to 50% of the inorganic particles in the layer can include additional pigment particles, the composition of which Examples include, but are not limited to, calcium carbonate, talc, zeolite, silica, alumina, titanium dioxide, and the like.

  The support used in the present invention can be any support commonly used as an inkjet receiver, such as resin-coated paper, paper, polyester. This support may alternatively be a porous synthetic polymer material such as porous extruded polyester or poly (lactic acid), or a microporous material such as that marketed under the trade name TESLIN by PPG Industries, Inc. of Pittsburgh, PA. Polyethylene polymer containing materials, TYVEK synthetic paper (DuPont Corp.), and OPPALYTE film (Mobil Chemical Co.) and other composite films listed in US Pat. No. 5,244,861.

  Translucent supports include plain paper, coated paper, synthetic paper, photographic paper support, melt extruded coated paper, and laminated paper, such as biaxially oriented support laminates. Biaxially stretched support laminates are described in U.S. Pat.Nos. 5,853,965, 5,866,282, 5,874,205, 5,888,643, 5,888,681, 5,888,683 and 5,888,714. It is described in the specification. These biaxially oriented supports include paper bases and biaxially oriented polyolefin sheets, typically polypropylene laminated to one or both sides of the paper base.

  Transparent supports include cellulose derivatives such as cellulose esters, cellulose triacetate, cellulose diacetate, cellulose acetate propionate, cellulose acetate butyrate; polyesters such as poly (ethylene terephthalate), poly (ethylene naphthalate), poly ( 1,4-cyclohexanedimethylene terephthalate), poly (butylene terephthalate) and copolymers thereof; polyimides; polyamides; polycarbonates; polystyrenes, polyolefins such as polyethylene or polypropylene; polysulfones; polyacrylates; polyetherimides; Is mentioned.

The support for the coated ink retaining layer is preferably selected from plain paper, more preferably untreated (uncoated paper). The term “plain paper” refers to paper that has a coating of less than 1 g / m ² applied over untreated paper. The term “untreated paper” refers to a cellulosic paper whose surface does not have a continuous layer or a coating of a separate material on the cellulose fibers of the paper, however the paper is sized. It may be treated with a material, or part of the surface may be impregnated with a treatment material.

  The thickness of the support used in the present invention can be 12-500 [mu] m, preferably 75-300 [mu] m, for example, untreated paper of 4-5 mil thickness (100 micrometers).

  A wide range of ink receptive front coating compositions can be used in the ink jet recording element of the present invention, but only a few examples will be mentioned. In some cases, the ink jet recording element has a porous ink-receptive interlayer on top of the base layer, below the topmost porous image-receiving or glossy layer, in addition to the porous base layer closest to the support. Can be included.

In one such embodiment, the drying mass coverage based on the base layer, optionally contains one layer or two layers or more sub-layers, but the amount of 15g ^/ m ² ~60g / m 2 And the upper layer is present in an amount of 1-10 g / m ² . Preferably, this top layer contains a relatively high concentration of the mordant in the ink jet medium and is optionally the only layer with a mordant, preferably in the form of a cationic polymer. .

Accordingly, one embodiment of the present invention is useful for either dye-based or pigment-based ink jet printing, on an absorbent support, in order:
(A) a porous base layer comprising a polymer binder and 80% by mass or more of inorganic particles having a particle size of 0.3 to 5 micrometers,
(B) any one or more porous ink-receptive interlayers comprising 80% by weight or more of inorganic particles, and (c) a porous top gloss comprising 80% by weight or more of the total inorganic particles. Relates to an ink jet recording element comprising a layer, wherein the inorganic particles have a median particle size of less than 200 nm and in some cases are a mixture of particles.

When describing ink jet recording elements, the following conventions usually apply:
The term “porous layer” is used herein to define a layer that is characterized by absorbing applied ink by capillary action rather than liquid diffusion. Although porosity can be affected by the ratio of particles to binder, porosity is based on pores formed by voids between the particles. The porosity of the layer can be predicted based on the critical pigment volume concentration (CPVC). An ink jet recording element having one or more porous layers, preferably substantially all layers, on a support, although at least the support is not considered porous, Ink jet recording element ".

  With respect to this method, the term “image-receiving layer” is intended to define a layer that is used as a pigment-capture layer, a dye-capture layer or a dye and pigment-capture layer, in which the printed image Exists substantially through this layer. Preferably, the image receiving layer contains a mordant for dye-based ink. In the case of dye-based inks, the image may optionally be present in more than one image receiving layer.

  In the context of this method, the term “base layer” (often also referred to as “sump layer” or “ink carrier liquid receiving layer”) is used herein under at least one other ink retaining layer. A layer is used to mean a layer that absorbs a substantial amount of ink carrier liquid. In use, a substantial amount, preferably most, of the carrier liquid for the ink is received in this base layer. The base layer is not on the image containing layer and is not itself an image containing layer (pigment capture layer or dye capture layer). Preferably, the base layer is the ink retaining layer closest to the support.

  The term “ink-receiving layer” or “ink-retaining layer” includes any or all of the layers on the support, which receive the applied ink composition and image in the inkjet recording element. Absorbs or captures any portion of one or more of the ink compositions (including ink carrier liquid and / or colorant, even if later removed by drying) used to form the ink. Thus, the ink receiving layer can include an image receiving layer in which the image is dyed and / or pigmented, a base layer, or any further layer, for example the base of an ink jet recording element. Formed between the layer and the top layer. Usually, all layers on the support are ink receptive. The support on which the ink receiving layer is coated can also absorb the ink carrier liquid and is referred to as an ink absorbing or absorbent layer rather than an ink receiving layer.

  These layers may optionally be divided into sublayers, preferably directly adjacent sublayers, in which case these sublayers are independently, individually and collectively this layer. Meet the restrictions. Preferably, if divided, then there are only two or three sublayers to make this layer.

  Preferably, an unprinted inkjet recording element exhibits a 20 degree gloss of 15 Gardner gloss units or more. More preferably, the 60 degree gloss of an unprinted inkjet recording element is 40 Gardner gloss units or more, more preferably 20 degree gloss is 20 Gardner gloss units or more, and 60 degree gloss is 50 Gardner gloss units. More than a unit.

In a preferred embodiment, the ink jet recording medium provides photographic image quality and the ability to absorb ink flow rates of 5.0 × 10 ⁻⁴ mL / cm ² / sec or higher without compromising image quality. This ink flow rate prints a 4 "x 6" photo at an addressable resolution of 1200 x 1200 pixels per inch with an average ink volume of 10.35 picoliters (pL) per pixel in 42 seconds. Corresponding to the case, the printing of a given pixel by a plurality of coating steps is completed in less than 4 seconds.

  In one particular embodiment, the base layer comprises inorganic particles such as calcium carbonate, magnesium carbonate, insoluble sulfates (eg barium sulfate or calcium sulfate), hydrous silica or silica gel, silicates (eg aluminosilicates), Contains titanium dioxide, talc, and clay or components thereof (eg, kaolin or kaolinite). The preferred particles as the majority of the inorganic particles in the base layer are structured pigments, in which the dispersed particles have a low internal porosity or are internal as compared to microporous pigments. Does not have porosity. Structured pigments have a non-spherical morphology, which does not allow close packing in the dried coating. Precipitated calcium carbonate (PCC) is an example of a structured pigment that provides high porosity in ink jet coatings. For example, precipitated calcium carbonate having a decentered trihedral morphology has been used to provide ink jet printing ink absorption. The base layer preferably contains inorganic particles in the range of 50% by mass to 90% by mass.

In such an embodiment, as the layer above the base coat, the top ink-receiving layer and any optional intermediate layer comprise inorganic particles selected from metal oxide particles, which are roughly It can be divided into particles made by a wetting process and particles made by a drying process (gas phase process). The latter type of particles is called fumed particles or pyrolytic particles. In the gas phase method, a flame hydrolysis method and an arc method are commercially used. The term “flame hydrolysis” is understood to mean the hydrolysis in the gas phase of a flame produced by the reaction of a fuel gas, preferably hydrogen and oxygen, of a metal or non-metallic compound. Highly dispersed, non-porous primary particles are initially formed which coalesce to form aggregates as the reaction continues, and these aggregates further coalesce to form agglomerates can do. In a preferred embodiment, these initial particles have a BET surface area of 5 to 600 m ² / g. While fumed metal oxides are produced in a gas phase process, colloidal metal oxides are not and can be distinguished from both fumed metal oxides made by a drying process.

  Fumed particles are suitable for forming a three-dimensional structure having a high void ratio. Pneumatic or pyrogenic particles are smaller, aggregates of initial particles. Although the initial particles are not porous, the aggregate contains a significant void volume and thus allows rapid liquid absorption. These void-containing aggregates allow the coating to retain significant capacity for liquid absorption, even if this aggregate particle is closely packed, which minimizes the void volume between the particles of the coating. To.

  For example, fumed silica for optional optional use in the present invention is described in U.S. Pat.No. 6,808,769 to Batz-Sohn et al., U.S. Pat.No. 6,964,992 to Morris et al. And U.S. Pat. It is described in the specification. Examples of fumed silica are given in the examples below and, for example, from Cabot Corp. under the name of the group of trademarks CAB-O-SIL silica or from Degussa, of the group of trademarks AEROSIL silica. It is commercially available under the name. Various fumed aluminas are also readily available commercially. For example, fumed alumina particles for any optional use in the present invention are described in US Patent Application Publication No. 2005/0170107.

  Preferably, substantially all of the particles in the uppermost ink receiving layer gloss generating layer ("gloss layer"), the image receiving layer for an ink jet recording element have an average primary and secondary particle size of 300 nm or less. Yes.

  Voids in the gloss layer provide a path for ink to penetrate appreciably into the base layer, thus allowing the base layer to contribute to drying time. Therefore, the voids in the glossy layer are in communication (connected) with the voids in the base layer for optimal interlayer absorption, and preferably (but essential) compared to the voids in the base layer. Rather, it has an equivalent or slightly larger void size. In one embodiment, the upper gloss layer contains less than 10% by weight binder based on the total solids in the layer. The binder in this upper gloss layer can be selected from the same binders as in the base layer. Any of the above hydrophilic binders can be used as well, but poly (vinyl alcohol) is also a preferred binder here, such as polyvinyl acetate, polyvinyl pyrrolidone, gelatin, poly (2-ethyl-2-oxazoline), Poly (2-methyl-2-oxazoline), poly (acrylamide), chitosan, poly (ethylene oxide), methylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, and the like.

  The particle to binder mass ratio of the particles and optional binder used in the porous base layer and gloss generating ink receiving layer is in the range of 100: 0 to 60:40, preferably 100: 0 to 90:10. be able to. In general, layers having a particle to binder ratio outside the above range are usually not sufficiently porous to give good image quality. In a preferred embodiment of the invention, the volume ratio of particles to polymer binder in both the base layer and gloss generating ink receiving layer is from 1: 1 to 15: 1.

  Conventional additives can be included in the ink-receiving layer of the present invention, which may depend on the specific application of the recording element. Such additives that may optionally be included in the ink receiving layer of the ink jet recording element include cross-linking agents, rheology modifiers, surfactants, UV absorbers, biocides, lubricants, dyes, Examples include optical brighteners and other commonly known additives. Additives can be added in light of the fact that the ink-receiving layer of the inkjet recording element may come into contact with other image recording products or the drive or transport mechanism of the image recording device, and thus glossy. Additives such as eraser particles can be added to the extent that they do not degrade the desired properties.

  All coated layers of the ink jet recording element on the front or back side of the support can be made by various coating methods including wire wound rod coating, slot coating, slide hopper. Examples include, but are not limited to, coating, gravure, curtain coating, and the like. Some of these methods allow for simultaneous coating of two or more layers, which is preferred from an economic point of view of manufacture.

  The back layer may be an ink receiving layer, such as a glossy layer, coated on the front side, then coated on the back side of the support, or first coated on the back side, and then one or more layers of the ink receiving layer. A layer can be coated on the front surface. However, after the ink receiving layer including the gloss layer has been coated, it is preferable to coat the back layer on the back surface of the support.

  After coating and drying the back layer, this layer can be subjected to calendering by conventional calendering equipment. However, excessive calendering promotes smoothing, which increases the coefficient of static friction between the back layer and the glossy layer, leading to poor transport of the sheet in the printing press. Therefore, appropriate control of the manufacturing method is necessary.

  As described above, in the present invention, the coefficient of static friction between the uppermost layer and the rear surface coating layer on the image forming surface is appropriately selected, and the type, amount and coating amount of the pigment and binder in the uppermost image forming layer are appropriately selected. It is necessary to adjust to 0.9 or less, preferably 0.2 or more by appropriately selecting the kind, amount and coating amount of the pigment and binder in the uppermost layer on the back surface. If the static friction coefficient is too small, when many sheets are stacked, they cannot be stably stacked.

  The static back-to-roller or “picking” COF must be larger than the front-to-back COF to allow the roller to take the media from the media stack and slide it into the press. . The difference between the back-to-roller COF and the back-to-front COF must be greater than 0.75, preferably greater than 0.9. In order to allow the media to be transported in the printing press, the dynamic back-to-roller or “feed” COF must be larger than the front-to-back COF. The delta COF must be greater than 0.40, preferably greater than 0.6.

  Other aspects of the invention include: (A) providing an ink jet printer responsive to a digital data signal, (B) supplying the ink jet recording element having the above back coat to the ink jet printer, (C ) Supplying the inkjet printer with an inkjet ink composition; and (D) printing on the inkjet recording element with the inkjet ink composition in response to the digital data signal. The present invention relates to an inkjet printing method including the steps.

The following examples further illustrate the invention.
Example Curl Evaluation Media samples were tested for curl after production and before printing in the following procedure. Media samples were cut to 10 cm x 15 cm and conditioned for 24 hours at Condition 1 (12 ° C and 20% RH), and additional samples were conditioned at Condition 2 (27 ° C and 80% RH). Following the conditioning period, edge rise was measured at each of the four corners of each sample, and the results of 10 samples were averaged. Positive curl indicates curl in the direction of the image and negative curl indicates curl in the direction of the back side. The absolute value of the curl difference between condition 1 and condition 2 was calculated as “delta curl”.

Picking and Feeding Test Media samples were cut into 10 cm x 15 cm and stacked on 10 sheets and allowed to stand. This stacking was conditioned under condition 1 in the curl evaluation. Following the 24 hour period of conditioning, this stack was fed into a KODAK 5300 press. Ten prints were made continuously and then the media supply tray was refilled with an additional stack of 10 sheets until 100 prints were made. The unsuccessful transport is summarized in a table. The types of unsuccessful observed include unsuccessful picking, unsuccessful correct feeding, and feeding two sheets at the same time.

Scratch Test The multi-point scratch behavior of the unprinted sample was evaluated according to the following procedure using a Single Arm Scratch device designed and manufactured by Eastman Kodak Company. Samples were conditioned for at least 18 hours at 23 ° C./50% RH prior to testing. After this conditioning period, three replicate samples for each coating were scratched using a polisher consisting of 3M 268XA TRIZACT film (A35MIC grade). A constant load of 180 grams and a scratch speed of 25 mm / sec were used. After the generation of scratches was completed, the samples were visually evaluated to classify the degree of damage.

The classification used for scratch evaluation is as follows.
1 = no visible scratches, no dusting 2 = slight scratching, very little dusting 3 = visible scratching, medium dusting 4 = large scratches, large dusting 5 = surface Damage, coating removed

Example 1
A paper support containing eucalyptus fibers at a basis weight of 180 g / m ² was prepared. Calcium carbonate (ALBAGLOSS-S, Specialty Minerals Inc.), silica gel (IJ 624, Gasil), styrene butadiene latex (CP692NA, Dow), poly (vinyl alcohol) (CELVOL 325, Celanese Corp.) on the image side surface The base layer aqueous coating composition, comprising a dry mass ratio of 65/21/11/2, was bead coated at 30 g / m ² and dried.

Colloidal boehmite (CATAPAL 200, Sasol Inc.), poly (vinyl alcohol) (GH23, Nippon Gohsei), glyoxal (CARTABOND GHF, Clariant) and boric acid were mixed with 95.38 / 4.25 / 0.25 / A second aqueous coating composition comprising a dry mass ratio of 0.12, and fumed alumina (PG008, Cabot Corp), boehmite (DISPAL 14N4-80, Sasol), poly (vinyl alcohol) (GH23, Nippon Gohsei) , Mordant (from Eastman Kodak Company), surfactant (ZONYL FSN, DuPont), glyoxal (CARTABOND GHF, Clariant) and boric acid, 41.7 / 36.5 / 5.3 / 15.7 / 0.3. a third aqueous coating composition comprising by dry weight ratio of /0.3/0.1, using a slide hopper bead coating, each 40 g / ^{m 2} and 2 g / ^{m 2,} the base layer coated above on top of Coated and dried at the same time.

Clay (HYDRAGLOSS 90, JM Huber Corp), poly (vinyl alcohol) (MOWIOL 28-99, Kuraray Inc), dispersant (COLLOID 211), glyoxal (CARTABOND GHF, Clariant) 91/8 / 0.9 / 0 A fourth aqueous coating composition comprising a dry weight ratio of 0.1 and a fifth coating composition comprising poly (vinyl alcohol) (MOWIOL 28-99, Kuraray Inc.) using a slide hopper bead coating method. , respectively 25 g / m ² and 3 g / m ^2, the image-receiving layer of the support on the surface opposite to coated simultaneously, and dried to give example I-1 of the present invention.

Comparative Examples C-1 to C-4 were prepared in the same manner as Example I-1, except that the back coating was changed as follows.
C-1: Only clay layer, no PVA skin coat C-2: Only PVA layer, no clay layer base coat C-3: Only clay layer increases clay / PVA ratio from 91/8 to 80/20 C- 4: No back coat

  The results of evaluation of picking and paper feeding, curling and wear resistance are shown in Table 1.

  The results shown in Table 1 above show that the acceptable curl before printing and “picking and feeding” with almost no error and no visible scratching or dusting are the two-layer backside used in the present invention. It shows that it is possible only with coating. If the clay-containing layer closer to the support is omitted, the curl is unacceptable. If the outermost layer consisting essentially of PVA is omitted, an error tendency will appear in the paper feed in the press mechanism.

Static and Dynamic Friction Coefficient Test This test was performed to determine the ratio of the frictional force that resists the movement of the media surface to the force applied perpendicular to the surface (medium mass). This test uses an Instron® device to determine the force required for the media to start moving from a static form (static force) and the force required for the media to continue to move at a constant speed (dynamic force). Was measured.

  The contact area was 6.5 square centimeters. The measurement was performed at 23 ° C. and relative humidity (RH) 50%. The dynamic speed was 47 cm / min and the normal force was 100 grams. These conditions were chosen to reproduce the conditions that the media would encounter in a Kodak Easyshare 5300® press.

  The coefficient of friction (static and dynamic) was measured for the roller material of the KODAK EASYSHARE 5300 press against the back side of the inkjet receiver and for the front side against the back side of the media. These results are shown in Table 2.

  The results shown in Table 2 show that the back-to-roller or “picking” static COF is used to allow the roller to take media from the media stack and slide into the press. It shows that it must be larger than the COF on the opposite side. The difference between the back-to-roller COF and the back-to-front COF must be greater than 0.75. Examples I-1, C-2 and C-4 meet this requirement. In order to allow the media to be transported in the printing press, the back-to-roller dynamic or “feed” COF must be greater than the front-to-back COF. Here the delta COF must be greater than 0.40. Examples I-1, C-2 and C-4 meet this requirement.

Example 2
This example shows the effect of changing the thickness of the outermost layer on the back side. Except that the PVA dry mass in the outermost layer of the back coat was varied in a range of ^{1g / m 2 ~6g / m 2} , to prepare a series of coating according to the procedure used in coating I-1 described above. After drying, 1 g / m ² of PVA corresponds to a thickness of about 1 micron. As in Example 1, curling and picking and paper feeding capabilities were evaluated and the results are shown in Table 3.

The results shown in Table 3 indicate that a hydrophilic polymer of ² g / m ² or more is desired in the outermost layer of the back coat in order to obtain a more reliable picking and feeding behavior. These results indicate that too thick a PVA layer can adversely affect the curl of a given paper and front coating. In this example, the upper limit of PVA reaches 5-6 g / m ² , but can be increased or decreased with different paper supports or front coatings.

Example 3
In this example, an alternative binder is used in the outermost layer of the back surface layer. A series of coatings were prepared according to the procedure in Example 1 except that a different polymer was used in the outermost layer of the back coat. The picking and feeding performance of these coatings was evaluated according to the procedure used in Example 1. These results are shown in Table 4.

  The results shown in Table 4 indicate that various polymer layers are suitable for the outermost back layer.

Example 4
This example shows the effect of the molecular weight and degree of hydrolysis of the polymer material (PVA) in the top layer of the back layer. A series of coatings were prepared according to the procedure in Example 1 except that a different type of poly (vinyl alcohol) was used in the outermost layer of the back coat. The characteristics and properties of the poly (vinyl alcohol) used are shown in Table 5. These coatings were evaluated as in Example 1 and the results are shown in Table 5.

  The results shown in Table 5 show that acceptable results are achieved by using PVA over a range of molecular weights (expressed by solution viscosity) and degree of saponification. The corresponding viscosity ranges from 20 to 52 and the degree of saponification ranges from 78% to 99%.

Example 5
A series of coatings were prepared according to the procedure in Example 1 except that different types of inorganic particles were used in the inner layer of the back coat. The features of the filler used are shown in Table 6 below. The coating was evaluated as in Example 1 and the picking and feeding, delta curl, and abrasion resistance evaluation results are also shown in Table 6.

  The results shown in Table 6 show that acceptable results are achieved even with other inorganic particles replacing the clay in the inner layer of Example 1.

Claims (4)

An ink jet recording element comprising a support having a front surface and a back surface, the ink jet recording element comprising:
(A) One or more porous ink receiving layers on the front surface of the support, and the total coverage of the one or more porous ink receiving layers is 15 g / m. One or more porous ink-receiving layers that are ^two or more, and (b) the following coated layers on the back surface of the support, in order from the support:
(I) A porous first back surface layer containing inorganic particles and a polymer binder having a solid content of 4% by mass to 50% by mass, and the coverage of the first back surface layer is ^{2 to} 50 g / m ^2. A porous first back layer, and (ii) a non-porous top second layer comprising 75% by weight or more of polymer material in solids on the porous first back layer. An ink jet recording element comprising: a non-porous uppermost second back layer, wherein the second back layer has a coverage of ² to 10 g / m ² .   The ink jet recording element of claim 1, wherein the support comprises paper that is not resin coated. An ink jet recording element comprising a support having a front surface and a back surface, the ink jet recording element comprising:
On the front surface of (a) said support, the porous ink-receiving layer of at least two layers, the overall coverage of the one or more layers of porous ink-receiving layer is Ru der 40 g / m ² or more, And (b) on the back surface of the support, in the order from the support, the following coated layers:
(I) a porous first backside layer containing 5 to 15 wt% of the polymer binder in the kaolin particles and solids, the coverage of the first backside layer is Ru der 15 g / ^{m 2} or more, and ( on the ii) porous first backside layer, non-porous topmost second backside layer containing more than 80 wt% of the Po Ribi Niruaruko Le in solids, the coverage of the second backside layer is 2 g / m ² or more, wherein the overall coverage of the coated layers on the backside, the ratio to the total coverage of the porous ink-receiving layer on the front of the support, 25 to 65 % Inkjet recording element. (A) preparing an ink jet printer responsive to a digital data signal;
(B) supplying the inkjet recording element according to claim 1 to the inkjet printer;
(C) supplying an inkjet ink composition to the inkjet printer; and (D) printing on the inkjet recording element using the inkjet ink composition in response to the digital data signal. An ink-jet printing method comprising the steps of: